package com.yzd.learnjava.reusing;


public class Car {
	public Engine engine = new Engine();
	public Wheel[] wheels = new Wheel[4];
	public Door left = new Door(), right = new Door();
	
	public Car() {
		for(int i = 0 ; i < 4; i++) {
			wheels[i] = new Wheel();
		}
	}
	public static void main(String[] args) {
		Car car = new Car();
		car.left.window.rollUp();
		car.wheels[0].inflate(72);
	}

}

class Engine{
	public void start() {}
	public void rev() {}
	public void stop() {}
}

class Wheel{
	public void inflate(int psi) {}
}
class Window{
	public void rollUp() {}
	public void rollDown() {}
}
class Door{
	public Window window = new Window();
	public void open() {}
	public void close() {}
}
